Ohuhu Electric Pencil Sharpener, Automatic, Both Battery and USB Powered, New Version 100% Kid Safe!- Automatic safety lock function function: The pencil sharpener stops operation once the shaving tray is removed. Never Over-sharpening! - Automatic idling once the pencil tip has been shaved within 0.3-0.5mm/0.01"-0.02". Now you will never worry a pointy tip to destroy your work. Replaceable Sharpener Core Design - greatly extending the service life. [1 * replacement core included] Sharp durable SK5 steel blade & large easy-clean shavings tray with faster and stable cutting performance. Multiple Power Sources - Can be powered by either USB (wire included) or 4 AA batteries (not included).